The present invention relates to an automatic pane cleaning system. The invention is particularly suited for windows of a high building, such as a skyscraper, but can also be used for automatically cleaning facade surfaces, or the like.
Automatic pane cleaning systems have already been suggested for cleaning windows of high buildings, the systems comprising a gondola which is suspended from ropes and has secured thereto a cleaning head which is guided by a control means over the window surfaces. The gondola has mounted thereon the associated components of the cleaning system, such as water tank, power generator, drive means for the cleaning head, conduits, etc. The gondola is e.g. suspended from a crane which is movable on rails positioned on the roof of the building. The crane displaces the gondola from window to window to perform a corresponding cleaning operation on the windows.
Water is supplied from an associated water tank to the cleaning head by means of a pump and, after the cleaning process, the water is sucked off again from the cleaning head together with the dirt removed from the pane and together with the sucked-in air. The dirt water/air mixture is received in a separate dirty water container in the suggested systems and must be disposed off at a later time.
Such a pane cleaning system has the drawback that a large supply of clean water must be provided on the gondola and that the sucked-off dirty water also requires a large container, resulting in considerable dimensions and a great weight of the lift cage.
EP-A-642758 discloses an automatic cleaning system whose cleaning head is divided into a cleaning chamber and a suction chamber. Furthermore, the system comprises a clean water chamber from which water is supplied to the one cleaning chamber, as well as a dirty water chamber into which the dirt/air chamber is sucked.
Hence, such an automatic cleaning system is operated with a relatively large amount of water being consumed.
U.S. Pat. No. 3,775,804 describes an automatic pane cleaning system which comprises a single chamber from which only air is sucked off. The water flows from a collection region through a conduit into a water container which is arranged below the cleaning head and connected to said head for joint movement, and from which the water is again pumped off and supplied through a conduit to the spray nozzles. The water is not cleaned so that said cleaning system can only efficiently clean panes if it operates with a large amount of water in which the dirt particles received by reason of the cleaning process are virtually not noticeable.